.
The denominators are different; therefore, the first step is to build the fractions to fractions with common denominators.
20 can be factored as follows: 20 = 4 5 and 24 can
be factored as follows: 24 = 4
6.
Rewrite the fractions where the denominators are in factored form.
.
It appears that the common denominators must have the factors 4, 5 and 6.
Multiply each fraction by the form of 1 that will yield denominators with the same set of factors. (i.e., you can find each set of factors in the denominator of the answer)
,
, and
.
Add the numerators: 600 + 18 + 5 = 623.
The answer is .
This answer is already reduced so you can skip step 4.